His emergence as a front runner changes the race -- and the nation

That idealistic sentiment began as part of the catechism of democracy, but through generations of rote it has degenerated into a kindergarten fable. Adults, of course, know the truth. The presidency is reserved for white men who have held high office and who have almost always avoided embracing a cause or expressing a sentiment that is far outside the mainstream of established opinion.

But there are rare moments when the truths that seemed self-evident begin to be re-examined. The recalibration is a slow process, and it does not always immediately lead to...